1. Field of the Invention
The present invention relates to welding of electronic circuit components and, more particularly, concerns improved mounting of welding electrodes to enhance and facilitate such welding.
2. Description of Related Art
Resistance welding of electronic circuit components can be carried out by a pair of elongated parallel electrodes, sometimes known as "duo-tip" electrodes, which are closely spaced but mutually insulated from one another and have tips that are designed to be moved down upon an area to be welded. When welding current is applied to the electrodes, current flows between the electrode tips through the parts of the workpiece to be welded. Flow of current through the workpiece between the electrodes has a preferred orientation with respect to the orientation of the workpiece. However, the various components in the workpiece may be differently oriented with respect to one another, requiring variable orientation of the workpiece relative to the electrodes. The fixed orientation of welding electrodes in resistance welding weld heads requires that the workpiece, together with the components mounted thereon, be rotated relative to the weld head to obtain proper relative orientation. Such rotation is cumbersome, time consuming and often restricted by available throat depth of the weld head. The prior art arrangement does not lend itself to rapid, efficient operation nor to automation of the welding operation.
Slip rings have been employed in the past for passing current through rotating connections. Such arrangements have been employed for low current circuits, currents having a magnitude considerably less than required for welding, and thus have not been adapted to application for high current resistant welding applications. Slip rings or other prior rotating contact arrangements may introduce a relatively high resistance at such contacts, which is acceptable because of the continuous motion. However, if a high welding current were to be applied through such contacts while they were not moving, the relatively high resistance at the contact junction could tend to weld the contacts.
Accordingly, it is an object of the present invention to provide for resistance welding in a manner and with apparatus that avoids or eliminates above mentioned problems.